GENOMICS DATA INTEGRATION REVEALS A ROLE OF INTRON ARCHITECTURE IN THE ALTERNA- TIVE SPLICING RESPONSE TO DNA DAMAGE

SCHOR IE; MUÑOZ MJ

Congreso; Joint Meeting of Bioscience Societies; 2017

DNA damage caused by conditions such us UV irradiation affects gene expression patterns by different mechanisms, also including switching between isoforms of the same genes by means of alter- native splicing (AS) regulation. Previous work uncovered a pathway that modulate AS patterns in UV-treated human keratynocites, in- volving the generation of pyrimidine dimers, the kinase ATR and the phosphorylation of RNA pol II, a major mediator of the response. Here we analyze alternative splicing regulation in response to DNA damage genome wide, integrating transcriptomics, proteomics and RNA binding protein target scanning. We have taken advantage of global characterization of AS patterns through RNA-seq in three conditions: untreated cells, UV-treated and UV-treated reverted by photolyase-mediated repair of damaged DNA. Analysis of the gene- ral architecture of the gene suggested that the length of the anking introns is well correlated with the direction of the AS effect: exon cassettes showing higher inclusion after DNA-damage have shor- ter introns than expected, while those showing lower inclusion have longer introns. Hypothesis testing using a logistic regression model con rmed the in uence of intron length and highlighted differences between both modes of regulation: only upstream intron was impor- tant for exon up-regulation, while both anking introns in uenced exon down-regulation. Our working model is that up-regulation is mainly mediated by a phosporylation-induced change in RNA pol II elongation rate, as previously reported, while down-regulation is related to splicing regulators binding both anking introns. Target scanning revealed that indeed longer introns tend to have a higher ratio between negative (hnRNP proteins) and positive (SR proteins) regulators. Finally, quanti cation of protein abundance in normal vs. UV-treated cells con rmed that hnRNP proteins but not SR proteins increase their abundance in this condition, further supporting our model.